Motion Tracking SystemResearch and Testing

Rochester Institute of Technology

DAVID J. MONAHAN (ME)

JIM K. STERN (ME)

JAHANAVI S. GAUTHAMAN (EE)

BRIAN D. GLOD (CE)

ASSIS E. NGOLO (CE)

CORY B. LAUDENSLAGER (EE)

BACKGROUND: National Science Foundation (NSF) has extensively helped RIT’s Assistive Devices family develop a strong relationship with the Nazareth College Physical Therapy Clinic. Physical therapists at Nazareth have long expressed a desire for portable motion tracking devices enabling monitoring of patients’ motion in their natural environments. Previously, two motion tracking projects, one tasked to track limb motion, and the second focusing on lower back (lumbar) motion were slated. Due to challenges identified from these prior motion tracking projects, the two were combined to create this P10010, project. Instead of creating a fully functional motion tracking system, P10010 will focus on developing a foundation of knowledge for future motion tracking projects. To realize the need for patient-sensor interfaces options, a sister team, P10011, was created with whom P10010 will work closely.

MISSION STATEMENT:To research sensors and implementation methods for portable motion tracking systems capable of measuring patients' range of motion in their natural environments. The various aspects of a motion tracking system: sensors, a portable micro-controller, interface circuitry, software, and human interfaces are explored. The primary ranges of motion of interest:• Motion of a human limb, where a limb is defined as a 3-bar linkage, for example: upper leg, lower leg, and foot. • Motion of a human's lower back, where it is defined as the lumbar region, with 3 points of contact: sacrum, L1-L2, L3-L5. DESIGN SPECIFICATIONS:

SpecificationImportan

ceUnit

Ideal Value

Accuracy of Angles HighDegree

s ±1

Range of Angles HighDegree

s 360Size of Sensor Medium mm3 30x30x15Degrees of Freedom Medium Axis 3Size of Data Storage High GB 5Sampling Frequency High Hz 100Input Voltage High V 9Range of Data Transmission High Ft 5Weight of Micro-Controller High kg <.5

Set-up Time LowMinute

s 10Battery Life of the system High Hours 24Weight of Sensors High g 10Data transfer : Device to PC Low

Minutes 3

Angles are displayed for user High N/A

C3D Format

Wireless Solution Medium N/A WirelessComfort of Sensors on Person High

Subjective Yes

Attachment and Patient Safety High

Subjective

Patient is Safe

Budget High Dollars 500

TEST PLAN OVERVIEW:Component

Measurement of Interest

Test FixtureDegrees of Freedom & Range

Test FixtureAccuracy of Individual Measurements

Test Fixture Accuracy over Time

Test FixtureSafety/Nondestructive Testing

Sensors Output SignalSensors PowerSensors Output Signal QualitySensor Power

SensorsAccuracy of Individual Measurements

Sensors Accuracy over Time

SensorsDegrees of Freedom & Range

SensorsAccuracy/DOF with Enclosures

MCU  Read and StoreMCU PrecisionMCU FunctionalityMCU-PC Data FormatMCU DataMCU-Sensor Amplify SignalMCU-Sensor FilterMCU-Sensor PowerSensors & MCU's

Dimensions, Weight

P10010

ACKNOWLEDGEMENTS:Nazareth Physical Therapy Institute (Primary Customer)

Dr. Elizabeth DeBartolo (Team Guide), RIT Dept. of Mechanical EngineeringDr. Daniel Phillips (Sensors Guide), RIT Dept. of Electrical Engineering

Dr. Roy Czernikowski (Micro-controller Guide), RIT Dept. of Computer Engineering

CONCLUSIONS:• Sensors with 1-, 3-, and 6- degrees of freedom, accelerometers, inertial measurement units, and flex sensors were explored. • The sensors are currently being tested for individual functionality and usability in a system as a whole. • Test fixtures were designed and are being built for testing the sensors' accuracy, and leave opportunity for further testing. • Microcontroller is being tested for functionality, accuracy, and compatibility with sensors. • RIT research team, (P10011- Motion Tracking Human Interface), is working closely with this project to design sensor enclosures and attachment methods that can be easily sanitized, and are comfortable to wear.• Viable options for each sensor, and microcontroller capabilities will be compiled thoroughly at the end of project term.

ADDITIONAL INFORMATION: For additional information visit our team website online at: https://edge.rit.edu/content/P10010/public/Home.This material is based upon work supported by the National Science Foundation under Award No. BES-0527358. Any opinions, findings, and conclusions or

recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation.

FUTURE APPLICATIONS: • University and Biomedical Companies

R&D • Physical Therapy Clinics

• Athletic departments• Military

• Entertainment (Video Gaming, Animation)

• Bio-robotics• Medical Applications

CUSTOMER NEEDS:• The Product should be Portable • The Product should be Accurate • The Product should be Easy to Use • The Product Should be Sanitary • The Product should be Comfortable for Patient • The Product should be Durable

TEST FIXTURE DESIGNS CONCEPTS:

SELECTED MICRO-CONTROLLER:

Arduino Mega Microcontroller

WORK IN PROGRESS:• Sensors are being integrated with

fixtures for accuracy testing• Multiple Test fixture builds are being

completed • Microcontroller is being tested for

data-processing, ADC functionality, and storage

• Sensors will be connected to microcontrollers to test compatibility

and handling

PROJECT DELIVERABLES: • Provide future research teams with

sufficient tools to create a portable motion tracking device.

• Enhance the knowledge base of the RIT Biomedical Systems and Technologies

Track regarding sensor usage in human motion tracking.

SYSTEM OVERVIEW:

SELECTED SENSORS:

Resistive Response Flex Sensor

+/-2g Tri-axis Accelerometer

6 DoF Razor Ultra-Thin IMU

Digital Output "Piccolo“

Accelerometer

6 DoF- Atomic IMU